粉煤灰掺量对混凝土抗冻性能的影响规律研究

Study on the Influence of Fly Ash Content on the Frost Resistance of Concrete

寒冷地区,冻融循环作用是导致混凝土结构发生破坏的最主要原因。为研究粉煤灰掺量对混凝土抗冻性能的影响,本文对不同粉煤灰掺量的C35基准混凝土展开冻融循环试验,研究它们质量和弹性模量随冻融次数的变化规律,得到了以下几个主要成果:(1)随着冻融程度的加深,粉煤灰混凝土的质量损失会越来越快,甚至成倍数增长。(2)粉煤灰掺量小于24%时,粉煤灰掺量的大小对粉煤灰混凝土的质量影响很小;而当粉煤灰掺量大于24%时,随着粉煤灰掺量的增加,混凝土质量损失率将急剧增大,而且增大速率越来越快。(3)随着粉煤灰掺量的增加,粉煤灰混凝土的弹性模量会出现先增加后减小的变化规律,当粉煤灰掺量为20%左右时,混凝土的相对弹性模量最大。

In cold regions, the freezing and thawing cycle is the most important cause of the destruction of concrete structures. In order to study the effect of fly ash content on the antifreeze performance of concrete, the test for freezing and thawing cycles of different C35 reference concretes with different fly ash content was done and their mass and elastic modulus variation with freezing and thawing times were studied. The following results have been obtained： （1） With the deepening of the freeze-thaw level, the mass loss of fly ash concrete will be faster and faster, and it will even increase in multiples. （2） When the content of fly ash is less than 24%, the amount of fly ash content has little effect on the quality of fly ash concrete. While fly ash content is more than 24%, the concrete mass loss rate will increase sharply, and the rate of increase will be faster and faster with the increase of fly ash content. （3） With the increase of fly ash content, the elastic modulus of fly ash concrete will increase first and then decrease. When the amount of fly ash is about 20%, the relative elastic modulus of concrete is the largest.